"The conventional symbol for current is I , which originates from the French phrase' intensité de courant', or in English 'current intensity'. This phrase is frequently used when discussing the value of an electric current, but modern practice often shortens this to simply current. The symbol was used by André-Marie Ampère, after whom the unit of electric current is named, in formulating the eponymous Ampère's force law which he discovered in 1820. The notation travelled from France to Britain, where it became standard, although at least one journal did not change from using C to I until 1896."

I had an older electronics teacher in the 70's who insisted that Hz was "cycles" so it was correctly "Hz per sec". When I pointed out that my physics text said Hz was cycles per sec he informed me that "This was electronics, not physics".